Population Genetic Structure of Brook Trout in the Loyalsock Creek Watershed

Elaine Langone Center, Terrace Room

The rarity and magnitude of large disturbance events produce unpredictable changes to aquatic ecosystems. In particular, high stream flows can result in an immediate loss of fish populations and reduce genetic diversity through bottleneck effects. Conversely, high stream flows may increase population viability by facilitating movement of individuals among populations and by increasing habitat heterogeneity. In 2011, a 500-year flood event occurred in Loyalsock Creek causing catastrophic loss of many fish populations. Populations have since recovered, with some exceeding pre-flood size. However, the genetic structure of recovered populations is uncertain. As such, it is unknown whether the flood increased genetic connectivity by temporarily increasing population connectivity, or has induced loss of genetic diversity through founder effects. In summer 2015, we sampled 27 tributaries of the Loyalsock Creek to determine the genetic structure of adult brook trout (Salvelinus fontinalis) populations. Results will help inform management of brook trout populations in Loyalsock Creek and future studies concerning the behavior and movement of brook trout related to climate change and spawning habitat use.